import re

# 匹配任意小写字母
pattern = r'[A-Z]'
text = 'A1b2C3'
matches = re.findall(pattern, text)
print(matches)  # 输出: ['b']

# 匹配任意数字
pattern = r'[0-9]'
text = 'A1b2C3'
matches = re.findall(pattern, text)
print(matches)  # 输出: ['1', '2', '3']